Insulin is a hormone produced by the beta cells of the pancreas. Its primary function is to regulate glucose metabolism by allowing cells to absorb glucose from the bloodstream for energy production or storage. Beyond glucose regulation, insulin influences lipid metabolism, protein synthesis, and vascular function.
When insulin signalling functions normally, glucose levels remain stable, triglyceride production is controlled, and metabolic systems operate efficiently. However, when tissues become less responsive to insulin, a compensatory rise in insulin secretion occurs. This compensatory state is known as insulin resistance. The American Diabetes Association recognises insulin resistance as a key underlying mechanism in type 2 diabetes and metabolic syndrome (American Diabetes Association, Standards of Care 2023).
Insulin resistance occurs when muscle, liver, and adipose tissue cells do not respond effectively to insulin. As a result, higher levels of insulin are required to maintain normal blood glucose levels. Over time, the pancreas may struggle to sustain this increased production.
This early stage often develops years before fasting glucose or HbA1c levels become abnormal. Research published in The Lancet has demonstrated that hyperinsulinaemia frequently precedes the development of overt diabetes (Reaven, 1988).
Importantly, insulin resistance is not limited to glucose metabolism. Elevated insulin levels influence lipid synthesis in the liver, contribute to elevated triglycerides, and may promote endothelial dysfunction.
Insulin resistance is strongly associated with multiple cardiometabolic conditions. It plays a central role in the development of type 2 diabetes, but it is also linked to dyslipidaemia, non-alcoholic fatty liver disease, polycystic ovarian syndrome (PCOS), and hypertension.
A review in Circulation highlights that insulin resistance contributes to atherosclerotic cardiovascular disease through effects on lipid metabolism, inflammation, and vascular tone (Reaven, 2011).
In women, insulin resistance is a key driver of PCOS pathophysiology, as described in The Journal of Clinical Endocrinology & Metabolism (Dunaif, 1997).
This broader impact underscores why early identification is clinically important. If persistent insulin resistance is suspected, a detailed evaluation of metabolic risk factors may be helpful.
Most screening strategies focus on fasting glucose or HbA1c. However, fasting insulin levels may rise long before glucose levels become abnormal.
Although there is no universal consensus on a single “optimal” fasting insulin value, elevated fasting insulin in the presence of normal glucose may suggest early insulin resistance. Some clinicians also use the HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) as a surrogate marker in research and clinical practice.
It is important to interpret fasting insulin within the context of overall metabolic health, including waist circumference, triglycerides, HDL cholesterol, and blood pressure.
Individuals concerned about early metabolic dysfunction may benefit from a comprehensive metabolic and cardiovascular risk assessment.
Evidence consistently demonstrates that lifestyle modification remains the cornerstone of improving insulin sensitivity.
The Diabetes Prevention Program (DPP) trial showed that structured lifestyle intervention involving dietary change and physical activity significantly reduced progression to type 2 diabetes (Knowler et al., 2002).
Regular resistance training increases skeletal muscle glucose uptake, while aerobic activity improves mitochondrial efficiency. Dietary patterns emphasising whole foods, fibre, moderate protein, and reduced ultra-processed carbohydrate intake are associated with improved insulin sensitivity. Weight reduction, even in modest amounts, has been shown to improve hepatic insulin sensitivity and reduce triglyceride production.
Traditional medical systems, including Ayurveda, describe metabolic imbalance in terms of impaired digestive and metabolic function. While terminology differs from modern endocrinology, both frameworks recognise the importance of early correction of metabolic dysregulation.
From a preventive standpoint, structured lifestyle optimisation focused on sleep, dietary rhythm, stress regulation, and physical activity forms the foundation of long-term metabolic health. Where appropriate, an individualised metabolic care plan may help address early dysfunction before progression to overt disease.
Insulin resistance develops gradually and often without symptoms. By the time blood glucose rises, metabolic stress may have been present for years. Early detection, structured lifestyle modification, and appropriate clinical evaluation can significantly reduce long-term cardiometabolic risk. Understanding insulin resistance is not about fear. It is about recognising early signals and responding proactively.
American Diabetes Association. Standards of Care in Diabetes—2023. [LINK]
Reaven GM. Banting lecture 1988: Role of insulin resistance in human disease. [LINK]
Reaven GM. Insulin resistance and cardiovascular disease. [LINK]
Dunaif A. Insulin resistance and the polycystic ovary syndrome. J Clin Endocrinol Metab. [LINK]
Knowler WC et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention. New England Journal of Medicine. [LINK]
This article is intended for educational purposes only and does not replace medical consultation. Diagnosis and management of insulin resistance, diabetes, or metabolic disorders should be undertaken by a qualified healthcare professional. Lifestyle interventions complement but do not substitute appropriate medical care.
